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HYSEP: A COMPUTER PROGRAM FOR STREAMFLOWHYDROGRAPH SEPARATION AND ANALYSIS

U.S. GEOLOGICAL SURVEYWater-Resources Investigations Report 96-4040

HYSEP: A COMPUTER PROGRAM FOR STREAMFLOWHYDROGRAPH SEPARATION AND ANALYSIS

by Ronald A. Sloto and Michèle Y. Crouse

U.S. GEOLOGICAL SURVEYWater-Resources Investigations Report 96-4040

Lemoyne, Pennsylvania1996

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U.S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY

Gordon P. Eaton, Director

The use of firm, trade, and brand names in this report is for identification purposes onlyand does not constitute endorsement by the U.S. Geological Survey.

For additional information Copies of this report may bewrite to: purchased from:

District Chief U.S. Geological SurveyU.S. Geological Survey Branch of Information Services840 Market Street Box 25286Lemoyne, Pennsylvania 17043-1586 Denver, Colorado 80225-0286

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CONTENTS

Page

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Purpose and scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Limitations and cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Hydrograph-separation methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Fixed-interval method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Sliding-interval method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Local-minimum method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Program input requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Program output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Hydrograph separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Cumulative annual base-flow distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Flow duration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Seasonal flow distribution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Daily-values files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

How HYSEP works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13User interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Data panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Assistance panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Instruction panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Special files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

System defaults—TERM.DAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Session record—HYSEP.LOG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Error and warning messages—ERROR.FIL . . . . . . . . . . . . . . . . . . . . . . . 17

Program options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Default settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Specifying input files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Selecting WDM file data sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Add. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Browse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Find . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Selecting program output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Data files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Modifying plot parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Selection of hydrograph-separation method. . . . . . . . . . . . . . . . . . . . . . . . . . . 28Execution of the base-flow separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30References cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

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CONTENTS—CONTINUED

Page

Appendix 1. Annual base-flow summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Appendix 2. Monthly summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Appendix 3. Cumulative-distribution table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Appendix 4. Flow-duration table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Appendix 5. Seasonal-distribution table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Appendix 6. Special files. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

TERM.DAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42HYSEP.LOG. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

ILLUSTRATIONS

Figures 1-7.Graphs showing:

1. Daily mean streamflow and estimated base flow forFrench Creek near Phoenixville, Pa., 1992 . . . . . . . . . . . . . . . . . . . . 4

2. Hydrograph analysis using the fixed-interval method forFrench Creek near Phoenixville, Pa., April 1992. . . . . . . . . . . . . . . . 5

3. Hydrograph analysis using the sliding-interval method forFrench Creek near Phoenixville, Pa., April 1992. . . . . . . . . . . . . . . . 6

4. Hydrograph analysis using the local-minimum method forFrench Creek near Phoenixville, Pa., April 1992. . . . . . . . . . . . . . . . 7

5. Cumulative distribution function of mean annual streamflow,estimated mean annual surface runoff, and estimatedmean annual base flow for French Creek nearPhoenixville, Pa., 1969-92 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

6. Duration of total streamflow, estimated surface runoff,and estimated base flow for French Creek nearPhoenixville, Pa., 1969-92 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

7. Estimated mean monthly surface runoff and base flow forFrench Creek near Phoenixville, Pa., 1969-92. . . . . . . . . . . . . . . . . 12

8. Basic screen layout and commands for HYSEP . . . . . . . . . . . . . . . . . . . . 14

9. Opening screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

10. Hierarchy of menus in HYSEP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

11. Processing steps following selection of the Execute option. . . . . . . . . . . . 19

12. Browse (WSB) data-set information selection screen . . . . . . . . . . . . . . . . 21

13. Browse (WSB) data-set information screens . . . . . . . . . . . . . . . . . . . . . . . 22

14. Output options screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

15. Graphical output screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

16. Plot modification menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

17. Plot parameter modification menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

18. Base name and date specification screen . . . . . . . . . . . . . . . . . . . . . . . . . . 29

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TABLES

Page

Table 1. U.S. Geological Survey National Water Data Storage andRetrieval System (WATSTORE) daily values 80-characterrecord ASCII format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2. WDM file data search options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3. Output file name suffixes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

APPENDIX 6 TABLES

Table 1. TERM.DAT parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2. MENCRA values and corresponding program response . . . . . . . . . . . . 35

3. Example TERM.DAT file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4. TERM.DAT parameters for color display(DOS-based computers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

5. Codes used for nonprinting characters in a log file. . . . . . . . . . . . . . . . . 41

6. Description of example log file. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

CONVERSION FACTORS AND ABBREVIATIONS

Multiply By To obtain

inch (in.) 25.4 millimeter

square mile (mi 2) 2.59 square kilometer

million gallons per day (Mgal/d) 0.04381 cubic meter per second

million gallons per day per squaremile [(Mgal/d)/mi2]

0.0169cubic meter per second per

square kilometer

cubic foot per second (ft3/s) 0.02832 cubic meter per second

cubic foot per second per squaremile [(ft3/s)/mi2]

0.01093cubic meter per second per

square kilometer

1

HYSEP: A COMPUTERPROGRAM FORSTREAMFLOW

HYDROGRAPH

SEPARATION AND ANALYSIS

By Ronald A. Sloto and Michèle Y. Crouse

ABSTRACT

HYSEP is a computer program that can be used to separate a streamflow hydrograph into base-flow and surface-runoff components. The base-flow component has traditionally beenassociated with ground-water discharge and the surface-runoff component with precipitationthat enters the stream as overland runoff. HYSEP includes three methods of hydrographseparation that are referred to in the literature as the fixed-interval, sliding-interval, and local-minimum methods. The program also describes the frequency and duration of measuredstreamflow and computed base flow and surface runoff. Daily mean stream discharge is used asinput to the program in either an American Standard Code for Information Interchange (ASCII)or binary format. Output from the program includes tables, graphs, and data files. Graphicaloutput may be plotted on the computer screen or output to a printer, plotter, or metafile.

INTRODUCTION

Hydrograph analysis is a useful technique in a variety of water-resource investigations.Separation of streamflow hydrographs into base-flow and surface-runoff components is used toestimate the ground-water contribution to streamflow. Hydrograph-separation techniques alsohave been used to quantify the ground-water component of hydrologic budgets and to aid in theestimation of recharge rates. In addition, base-flow characteristics determined by hydrographseparation of hydrographs from streams draining different geologic terranes have been used toshow the effect of geology on base flow (Sloto and others, 1991, p. 29-33). White and Sloto(1990) analyzed streamflow hydrographs from 309 Pennsylvania streamflow-measurementstations to estimate base-flow-frequency characteristics.

Hydrograph separation traditionally has been done manually. Two commonly used methods arebase-flow-recession methods (Olmsted and Hely, 1962; Riggs, 1963; Rorabaugh, 1963) andcurve-fitting methods (Pettyjohn and Henning, 1979; Linsley and others, 1982). Differenthydrologists using the same manual hydrograph-separation method commonly producedifferent base-flow estimates. The use of a computer program removes inconsistencies inherentin manual methods and substantially reduces the time required for hydrograph separation.Separation of a streamflow hydrograph is based on a mathematical technique that mimics theway that humans have been separating hydrographs, rather than on the physics of the process.Thus, although HYSEP consistently applies various algorithms that are commonly used forhydrograph separation, hydrograph separation remains a subjective process.

Computer hydrograph-separation methods were compared with published values determinedmanually for streams in southeastern Pennsylvania by Sloto (1991). Base flows estimated withcomputer methods agreed closely with those estimated by manual methods.

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PURPOSE ANDSCOPE

This report documents the streamflow hydrograph-separation and analysis program referred toas HYSEP. HYSEP employs a character-based interface and can be used on multiple platforms.The program separates streamflow hydrographs into base-flow and surface-runoff componentsand performs frequency and duration analyses on both components. This report describes theHYSEP program, the hydrograph-separation and analysis methods used, program design andoperation, input requirements, and program output.

The methods for streamflow hydrograph separation used in this program were adapted fromPettyjohn and Henning (1979) and were originally incorporated in 1982 into a computerprogram that used streamflow data in standard U.S. Geological Survey (USGS) daily-valuesformat. The version of the HYSEP program described by this report is coded so that othermethods of hydrograph separation can easily be incorporated when the methods arecomputerized. Figures and appendixes in this report were produced by use of HYSEP.

LIMITATIONS AND CAUTIONS

The streamflow hydrograph-separation methods used by this program are intended to provideestimates of base flow and surface runoff to streams. Generally, average annual estimates aremore reliable than monthly or daily estimates of base flow or surface runoff.

Base-flow estimates are affected by regulation, which changes the natural flow of a stream andinfluences both base flow and surface runoff. A flood-control reservoir, for example, slowlyreleases runoff after a storm, resulting in an apparent decrease in surface runoff and an apparentincrease in base flow. Regulation includes reservoir storage and releases, discharge from quarryand mine dewatering, discharge from sewage treatment plants, and diversion for water supply.White and Sloto (1990, p. 22) found that the effect of regulation is site specific; annual baseflows decreased for the majority of streams in the Delaware River Basin and increased for themajority of streams in the Susquehanna and Ohio River Basins subsequent to regulation.

The accuracy of estimates of base-flow-frequency characteristics depends on the period ofrecord used in the analysis. Record for a station operated during a period of extremeclimatological conditions, such as mostly dry years, exhibits a bias toward the extreme. A long-term station with record representative of long-term climatological conditions provides a morereliable base-flow estimate because extremes have less weight in the determination of base-flowcharacteristics.

Input data should be carefully checked. Plotting input data provides an excellent visual checkfor periods of suspect data. For large data sets, plotting the annual hydrograph to the screen foreach year of data provides a quick and efficient check on the validity of the input data and thehydrograph separation. The use of this program to analyze data from multiple stations with longperiods of record without carefully checking the input data may result in erroneous estimates ofbase flow and surface runoff. It is the responsibility of the user to correctly interpret theusefulness of any results for the specific application.

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HYDROGRAPH-SEPARATION METHODS

The HYSEP program uses three methods to separate the base-flow and surface-runoffcomponents of a streamflow hydrograph—fixed interval, sliding interval, and local minimum.These methods can be described conceptually as three different algorithms to systematicallydraw connecting lines between the low points of the streamflow hydrograph. The sequence ofthese connecting lines defines the base-flow hydrograph. The techniques were developed byPettyjohn and Henning (1979). Hydrograph separations for the streamflow-measurementstation French Creek near Phoenixville, Pa., using the three methods are shown in figure 1. Eachmethod is described below.

The duration of surface runoff is calculated from the empirical relation:

N=A0.2, (1)

where N is the number of days after which surface runoff ceases, and A is the drainage area insquare miles (Linsley and others, 1982, p. 210). The interval 2N* used for hydrographseparations is the odd integer between 3 and 11 nearest to 2N (Pettyjohn and Henning, 1979, p.31). For example, the drainage area at the streamflow-measurement station French Creek near

Phoenixville, Pa. (USGS station number 01472157), is 59.1 mi2. The interval 2N* is equal to5, which is the nearest odd integer to 2N, where N is equal to 2.26.

The hydrograph separation begins one interval (2N* days) prior to the start of the date selectedfor the start of the separation and ends one interval (2N* days) after the end of the selected dateto improve accuracy at the beginning and end of the separation. If the selected beginning and(or) ending date coincides with the start and (or) end of the period of record, then the start of theseparation coincides with the start of the period of record, and (or) the end of the separationcoincides with the end of the period of record.

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FIXED-INTERVAL METHOD

SLIDING-INTERVAL METHOD

LOCAL-MINIMUM METHODDIS

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1992

Figure 1. Daily mean streamflow and estimated base flow for French Creek near Phoenixville, Pa., 1992.

MEASURED FLOWESTIMATED BASE FLOW



5

FIXED-INTERVAL METHOD

The fixed-interval method assigns the lowest discharge in each interval (2N*) to all days in thatinterval starting with the first day of the period of record (fig. 2). The method can be visualizedas moving a bar 2N* days wide upward until the bar first intersects the hydrograph. Thedischarge at that point is assigned to all days in the interval. The bar is then moved 2N* dayshorizontally, and the process is repeated. The interval 2N* is 5 days in figure 2. For example,in the interval April 5 to 9, the lowest discharge, 49 ft3/s, is assigned as the base-flowcomponent to every day in that interval. The assigned values are then connected to define thebase-flow hydrograph.

APRIL 1992

Figure 2. Hydrograph analysis using the fixed-interval method for French Creek nearPhoenixville, Pa., April 1992.

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SURFACERUNOFF

BASEFLOW

6

SLIDING-INTERVAL METHOD

The sliding-interval method finds the lowest discharge in one half the interval minus 1 day[0.5(2N*-1) days] before and after the day being considered and assigns it to that day (fig. 3).The method can be visualized as moving a bar 2N* wide upward until it intersects thehydrograph. The discharge at that point is assigned to the median day in the interval. The barthen slides over to the next day, and the process is repeated. In the interval April 16 to 20, the

lowest discharge, 42 ft3/s, is assigned to April 18, the median day in the interval (fig. 3). Theassigned daily values are then connected to define the base-flow hydrograph.

APRIL 1992

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BASEFLOW

Figure 3. Hydrograph analysis using the sliding-interval method for French Creek nearPhoenixville, Pa., April 1992.

7

LOCAL-MINIMUM METHOD

The local-minimum method checks each day to determine if it is the lowest discharge in onehalf the interval minus 1 day [0.5(2N*-1) days] before and after the day being considered. If itis, then it is a local minimum and is connected by straight lines to adjacent local minimums(fig. 4). The base-flow values for each day between local minimums are estimated by linearinterpolations. The method can be visualized as connecting the lowest points on the hydrographwith straight lines. In figure 4, local minimums occur on April 9, 15, 21, and 24.

APRIL 1992

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BASEFLOW

Figure 4. Hydrograph analysis using the local minimum method for French Creek nearPhoenixville, Pa., April 1992.

8

PROGRAM INPUT REQUIREMENTS

The HYSEP program accepts daily mean stream discharge as input in either of two formats:(1) the standard USGS National Water Data Storage and Retrieval System (WATSTORE) dailyvalues, 80-character record American Standard Code for Information Interchange (ASCII)format (table 1) (Williams, 1975, p. A21-A23); or (2) the binary, direct access Watershed DataManagement (WDM) file format (Flynn and others, 1995, p. 12-14). Daily-values data in theWATSTORE format can be retrieved from the USGS WATSTORE or Automated DataProcessing System (ADAPS) data bases. Data in the WATSTORE daily values format can beconverted to the WDM format by the IOWDM program (Lumb and others, 1990, p. 163-211).Data for 1 station in the WATSTORE daily values format and up to 300 stations in the WDMformat can be processed at one time. A minimum of 1 and a maximum of 100 years of data perstation in either format can be processed.

Table 1. U.S. Geological Survey National Water Data Storage and RetrievalSystem(WATSTORE) daily values 80-character record ASCII format

[Columns 1-24 are integers; columns 25-80 are decimal numbers]

column numeric code

1 Format number—Daily values are designated by the number 3.

2-16 Station-identification number.

17-20 Calendar year—A four-digit number representing the calendar year.

21-22 Month—A two digit number representing the month.

23-24 Record number—A two-digit number representing the days of the month for thedata. The record number is coded as follows:

Number01020304

Days1-89-1617-2425-31

25-80 Daily values—Eight, seven-column fields (25-31, 32-38, 39-45, 46-52, 53-59,60-66, 67-73, 74-80) in which daily values are coded for the days designated.Blank fields are read as zero values.

9

PROGRAM OUTPUT

Program output options, including tables, graphs, ASCII files, and WDM data sets, aredescribed in the following sections. In the tables, missing values are designated by -1.0. Graphsmay be plotted on the computer screen or sent to a printer, plotter, or metafile.

HYDROGRAPHSEPARATION

The HYSEP program will produce an annual hydrograph of streamflow and estimated base flowfor each year of record processed (fig. 1). The period of record analyzed can begin with any dayof the calendar year. Tabular output from the hydrograph separation summarizes the quantity ofestimated base flow and surface runoff and the percentage of streamflow as base flow andsurface runoff. An annual summary of base flow in units of inches, cubic feet per second, andmillion gallons per day per square mile is provided by default (Appendix 1). Alternatively, amonthly summary can be selected that gives monthly values of mean streamflow (cubic feet persecond), total streamflow (inches), mean base flow (cubic feet per second and million gallonsper day per square mile), total base flow (inches), mean surface runoff (cubic feet per second),total surface runoff (inches), and percentage of streamflow as base flow (Appendix 2).

CUMULATIVE ANNUAL BASE-FLOW DISTRIBUTION

A cumulative distribution function accumulates all of the probabilities of values less than orequal to the value of interest. When the probability density curve (probability distribution) iscumulated from the left, probabilities of not exceeding various magnitudes are obtained; this iscommonly referred to as a frequency curve in hydrology (Riggs, 1968, p. 1-3). Cumulativedistributions commonly are plotted on a probability scale, such that the theoretical curve is astraight line.

Cumulative distribution functions of mean annual streamflow, estimated mean annual baseflow, and estimated mean annual surface runoff for the period of record of a station can betabled and plotted for any hydrograph-separation method. Mean annual base flows are arrangedin order of magnitude beginning with the smallest as number one. A Weibull plotting positionestimate of the probability (p) of an annual mean base-flow value being less than a particularmagnitude is calculated by

p = m/(n + 1), (2)

where m is the order number of the individual year in the sample, and n is the number of yearsof record.

The cumulative distribution function of mean annual streamflow, estimated mean annual baseflow, and estimated mean annual surface runoff for 1969-92 for French Creek nearPhoenixville, Pa., are shown in figure 5. Estimated mean annual base flow can be printed as atable (Appendix 3).

10

For mean annual base flow, the recurrence interval is the average interval of time during whichannual base flow will be less than a particular value. The recurrence interval is the inverse ofthe cumulative probability function. Recurrence interval (T) may be calculated by

T = (n + 1)/m = 1/p, (3)

where n is the number of years of record, and m is the order number of the individual year inthe sample.

PERCENTAGE OF TIME RUNOFF WAS LESS THANOR EQUAL TO INDICATED VALUE

RU

NO

FF,

IN IN

CH

ES

40

0.5 2 5 10 20 50 70 90 95 98 99.5

36

32

28

24

20

16

12

8

4

0

TOTAL STREAMFLOW

SURFACE RUNOFF

BASE FLOW

Figure 5. Cumulative distribution function of mean annual streamflow, estimatedmean annual surface runoff, and estimated mean annual base flow for FrenchCreek near Phoenixville, Pa., 1969-92.

11

FLOW DURATION

A flow-duration curve is the complement of a cumulative distribution function that shows thepercentage of time specified mean daily discharges were equaled or exceeded during a givenperiod (Searcy, 1959). The HYSEP program plots flow-duration curves for total streamflow,estimated base flow, and estimated surface runoff (fig. 6). A flow-duration table (Appendix 4)can be generated for total streamflow, estimated surface runoff, and estimated base flow.

PERCENTAGE OF TIME FLOW WAS EQUALED OR EXCEEDED

FLO

W, I

N C

UB

IC F

EE

T P

ER

SE

CO

ND

103

0.5 2 5 10 20 50 70 90 95 98 99.5

102

10

TOTAL STREAMFLOW

SURFACE RUNOFF

BASE FLOW

Figure 6. Duration of total streamflow, estimated surface runoff, and estimatedbase flow for French Creek near Phoenixville, Pa., 1969-92.

12

SEASONAL FLOW DISTRIBUTION

The HYSEP program will plot estimated mean monthly base flow and surface runoff as a bargraph (fig. 7). The graph shows seasonal differences in base flow and surface runoff. Theestimated mean monthly base flow and surface runoff for French Creek at Phoenixville, Pa., for1969-92 are shown in figure 7. The quantity of surface runoff exceeds that of base flow only inJune. In addition, a seasonal-distribution table (Appendix 5) can be generated for estimatedmean monthly base flow and surface runoff.

DAILY -VALUES FILES

Daily values of estimated base flow or surface runoff in the WATSTORE daily values format(table 1) can be written to a file by selecting the appropriate program option. The ASCII file thatis generated can be used as input to other applications.

AV

ER

AG

E M

ON

TH

LY D

ISC

HA

RG

E,

IN C

UB

IC F

EE

T P

ER

SQ

UA

RE

MIL

E

Figure 7. Estimated mean monthly surface runoff and base flow for French Creek nearPhoenixville, Pa., 1969-92.

2.5

2

1.5

1

0.5

0JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC

BASE FLOWSURFACE RUNOFF

13

HOW HYSEP WORKS

HYSEP was written to be portable and, therefore, can be used on multiple computer platforms.Installation procedures depend on the computer platform, and specific installation instructionsare distributed with the software. Once the software is installed, type “hysep” to start theprogram.

USERINTERFACE

Program interaction takes place in a screen 80 characters wide by 24 characters high. The basicscreen layout is shown in figure 8. Each screen consists of a list of available commandsdisplayed at the bottom and one or more boxed-in areas that are referred to as panels.Commands are used to obtain additional information and to move between screens. The threetypes of panels are data, assistance, and instruction. The data panel displayed at the top of thescreen is always present. Data panels contain menus, forms, tables, and text to permit userinteraction with the program. An assistance panel may be present depending on user or programassignments. When present, the assistance panel is displayed below the data panel (usually asthe middle panel) and contains information, such as help messages, valid range of values, anddetails on program status. The instruction panel is displayed above the available commandswhen the user is expected to interact with the program. When present, the instruction panelcontains information on what keystrokes are required to interact with the program.

Each screen can be identified by a name and the path selected to reach the screen. The screenname appears in the upper left corner of the data panel, where the words “screen name” appearin figure 8. The first screen displayed by the program is named “Opening screen.” Allsubsequent screens are named on the basis of the menu option or program sequence that causedthe current screen to be displayed. Screen names are followed by “(path)” (fig. 8), a string ofcharacters consisting of the first letter(s) of the menu options selected in order to arrive at thecurrent screen. In some cases, descriptive text may follow the path to further help identify thescreen. The path can aid in keeping track of the position of the current screen in the menuhierarchy. For example, “Open (WFO)” indicates that the menu option Open was selected andthat the path to this screen from the “Opening screen” consisted of three menu selections—Wdm, File, and Open.

COMMANDS

The screen commands and their associated keystrokes are described in figure 8. A subset of thescreen commands is available for any given screen. Most commands can be executed bypressing a single function key. (The designation for a function key is “F#” where # is the numberof the function key.) All of the commands can be executed in “command mode.” Command

mode is toggled on and off by pressing the semicolon (;) key1. In command mode, anycommand can be executed by pressing the first letter of the command name; for example, “o”or “O” for the Oops command. When commands are discussed in this report, the commandname is spelled out with the function key or keystroke given in parentheses. For example,Accept (F2) is the most frequently used command.

Use Help (F1) and Limits (F5) to obtain additional information about the current screen andStatus (F7) to obtain information on the state of the program. Cmhlp (;c) will displayinformation on the available commands. Use Quiet (F8) to close the assistance panel. To move

1 On some systems the F3 key and (or) the escape key (Esc) may also work.

14

Help: Accept: Prev: Limits: Status: Intrpt: Quiet: Cmhlp Oops

instruction type

F1 F4

assistance type

screen name (path)

Assistance panel

Instruction panel

Data panel

F2 F5 F6 F8F7

HYSEP 2.0

Figure 8. Basic screen layout and commands for HYSEP.

command associatedkeystrokes1

1The function keys will execute the commands on most computer systems. On all computer systems, the semicolon key (“;”)followed by the first letter (upper or lower case) of the command can be used to execute the commands. The F3 function key maynot be available on some systems.

description

Help F1or ;h

Displays help information in the assistance panel. The help information is updated as the usermoves from field to field in the data panel or to a different screen. The program automaticallycloses the assistance panel if a screen is displayed for which no help information is available.

Accept F2or ;a

Indicates that you have “accepted” the input values, menu option currently highlighted, or textmessage in the data panel. Selection of this command causes program execution to continue.

Cmhlp F3cor ;c

Displays brief descriptions of the commands available on the screen.

Oops F3oor ;o

Resets all data fields in an input form to their initial values.

Dnpg F3dor ;d

Displays next “page” of text in data panel. Available when all of the text cannot be displayed atone time.

Uppg F3uor ;u

Redisplays previous “page” of text in data panel. Available after execution of Dnpg (F3d).

Prev F4or ;p

Redisplays a previous screen. Any modifications in the data panel are ignored. Which screen isthe previous one may be ambiguous in some cases.

Limits F5or ;l

Displays valid ranges for numeric fields and valid responses for character fields. Information onfield limits is updated as the user moves from field to field in the data panel or to a differentscreen by using the arrow keys or the Enter (Return) key.

Intrpt F6or ;i

Interrupts current processing. Depending on the process, returns the program to the point of exe-cution prior to the current process or advances to the next step in the process.

Status F7or ;s

Displays program status information.

Quiet F8or ;q

Closes the assistance panel. Available when the assistance panel is open.

Xpad F9or ;x

Opens the assistance panel as a “scratch pad.” Text entered in the scratch pad is saved in a filecalled “XPAD.DAT”.

15

between screens, use Accept (F2), Prev (F4), Intrpt (F6), Dnpg (;d), or Uppg (;u). To reset thevalues in the data panel, use Oops (;o). Xpad (F9) is used to save typed information in a filecalled XPAD.DAT.

DATA PANEL

The four types of data panels are menu, form, table, and text. Menus offer a choice of two ormore options. Data values are entered or modified in one or more data fields of a form or table.General or specific information, program progress, messages, and results of analyses may bedisplayed in a text data panel. The data panel appears at the top of the screen (fig. 8). There are16 rows in the data panel when the assistance panel is closed and 10 rows when the assistancepanel is open.

A single option is selected from a menu that consists of two or more options. A menu optioncan be selected in two ways: (1) press the first letter (not case sensitive) of the menu option; ifmore than one menu option begins with the same letter, press in sequence enough characters touniquely identify the option; or (2) use the arrow keys to move the cursor to the option and thenexecute Accept (F2).

Forms may contain any number and combination of character, numeric, file name, or optionfields. Character fields may be a variable entry, such as a descriptive text string (case sensitive),or they may require a specific entry, such as “yes” or “no” (not case sensitive). The text string“none” in a field indicates that the field is undefined. Option fields are activated and deactivatedby positioning the cursor in the option field and pressing any key, such as the space bar. Usearrow keys to move up, down, and laterally between fields. The Enter (Return) key is used tomove forward through fields. Use Accept (F2) to accept the entered or modified data andcontinue with the program. Executing Oops (;o) sets all fields in the screen to their initial values.Executing Prev (F4) will cause the data values entered on the screen to be ignored and theprevious screen to be displayed.

Tables may contain any number and combination of character, numeric, and file name columns.As with forms, character fields may require a specific or a variable entry. Use arrow keys tomove up, down, and laterally between fields. The Enter (Return) key is used to move forwardacross rows and to the next row. Some tables may contain more rows than can be displayed inthe 10 or 16 rows of the data panel. In these cases, the table is divided into multiple screens. UseAccept (F2) to move forward through each of the screens for the table and to continue with theprogram after the last screen of the table. Executing Oops (;o) sets all fields in the screen to theirinitial values. Executing Prev (F4) will cause the data values entered on the screen to be ignoredand the previous screen to be displayed. Executing Intrpt (F6) will cause the data values enteredon the screen to be ignored and the remaining screens in the table to be skipped. Use Quiet (F8)to close the assistance panel and view the 16 lines of the data panel.

A text data panel may contain a warning or error message, a tabular list of data, a progressmessage for an activity that may take more than a few seconds, or other general information.Execute Accept (F2) to continue to the next screen. In cases where the displayed text requiresmore lines than the number available in the data panel, the Prev (F4), Dnpg (;d), and Uppg (;u)commands may be used to move forward and backward (scroll) through the screens. The up anddown arrows also may be used to move through the screens. Intrpt (F6) may be available topermit skipping the remaining screens of text.

ASSISTANCEPANEL

The assistance panel provides information to help the user enter data in the data panel or to allownote taking during a program session. The panel appears in the middle of the screen below thedata panel. A name corresponding to the type of assistance being provided is displayed in the

16

upper left corner of the panel, where the words “assistance type” appear in figure 8. The Help(F1), Limits (F5), Status (F7), Cmhlp (;c), and Xpad (F9) commands open the assistance panel.The program may open the assistance panel to display status information. Help and Limitsprovide information about the screen and data fields; Status provides information about thecurrent process; Cmhlp provides information about the available commands; and Xpad providesa “note pad” for making notes in the file XPAD.DAT. Use Quiet (F8) to close the assistancepanel.

Assistance panels display four lines at a time. In cases where the assistance information isgreater than four lines, the cursor moves into the assistance panel. Use the up and down arrowkeys to scroll through the information. If available, the Page Down and Page Up keys may beused to page through the information. Use the command mode toggle (;) to put the cursor backin the data panel.

INSTRUCTIONPANEL

The instruction panel provides information on how to interact with the current screen, such ashow to enter data or how to advance to another screen. This panel appears at the bottom of thescreen just above the screen commands (fig. 8). The instruction panel is present whenever theprogram requires input from the user. Up to four lines of text are displayed in an instructionpanel. If an invalid keystroke is entered, the information in the instruction panel is replaced withan error message. In this case, the panel name (upper left hand corner) changes from the usual“INSTRUCT” to “ERROR.” Once a valid keystroke is entered, the Instruct panel is redisplayed.

SPECIAL FILES

Three files are associated with the interaction between the user and the program. Systemdefaults that control how the program operates can be overridden by setting parameters in theoptional TERM.DAT file. A session record is written to the HYSEP.LOG file each time theprogram is run; all or parts of this file can be used as input to the program at a later time. Errorand warning messages, as well as some additional information, may be written to the fileERROR.FIL.

System Defaults—TERM.DAT

Certain aspects of the appearance and operation of the program are controlled by parameterswithin the program. These parameters specify things such as the computer system type, graphicoutput type, terminal type, program response to the Enter key, and colors. Each parameter is seton the basis of the preferences of users who tested the program. The preset values can beoverridden by creating a TERM.DAT file in the directory where the program is initiated (thecurrent working directory). The available parameters and the format of the TERM.DAT file aredescribed in Appendix 6. If a TERM.DAT file does not exist in the current directory, themessage “optional TERM.DAT file not opened, defaults will be used” is displayed briefly whenthe program starts. If the TERM.DAT file is present, the message “reading users systemparameters from TERM.DAT” is displayed.

Session Record—HYSEP.LOG

The keystrokes entered during a program session are recorded in the HYSEP.LOG file. Eachtime the program is run, a HYSEP.LOG file is created; if one already exists in the currentdirectory, it is overwritten. All or part of this file can be used as input to the program as a meansof repeating the same or similar tasks. To do this, first save the HYSEP.LOG file under adifferent name. Modify the file to contain only the sequence of commands that need to berepeated. Then, at any point in a subsequent program session, press the “@” key and a small filename panel appears. Then, type the name of the log file and press the Enter key. Appendix 6describes the use and format of the HYSEP.LOG file.

17

Error and Warning Messages—ERROR.FIL

Any error or warning messages produced during a program session are written to theERROR.FIL file. Each time the program is run, an ERROR.FIL file is created; if one alreadyexists in the current directory, it is overwritten. Diagnostic and summary reports also may bewritten to this file. Examine ERROR.FIL if an unexpected program response is encountered.

PROGRAM OPTIONS

Typing “hysep” at the operating system prompt starts the program. The Opening screen shownin figure 9 will appear. The data panel contains the Opening screen menu options, and theinstruction panel explains how to select the menu items. The following options are available:

Card Choose the Card option to specify an input file that contains daily streamflowvalues in WATSTORE daily values format.

Wdm Choose the Wdm option if the input data are in a WDM format file.

Output Choose this menu item to specify the format and content of the printed output,which can contain summary tables of the hydrograph separation and analysis.Computed daily base flow and surface runoff also can be selected for outputin the WATSTORE or WDM formats.

Plots Choose this option to specify plots and graphical output devices.

Method Choose this option to specify the hydrograph-separation method.

Execute This option is chosen after an input data file has been specified, all desiredtabular and graphical output options have been defined, and the hydrograph-separation method has been chosen. Choosing this option initiates executionof the hydrograph separation.

Query Select Query to display information on who to contact for technical support.

Return Choose this option to terminate the program.

Figure 9. Opening screen.

18

The Return option is included on almost all menu screens. On menus other than the Openingscreen menu, choosing the Return option will return to the previous menu. Return performs thesame function as the Prev (F4) command on forms and tables.

The overall structure of the program and the processing steps that take place upon selection ofthe Execute option are diagramed in figures 10 and 11.

DEFAULT SETTINGS

At a minimum, the Card or Wdm option must be chosen to specify the input data file before theExecute option can be chosen. If no other menu options are chosen, the hydrograph separationwill be performed by use of the following default settings: (1) the fixed-interval hydrograph-separation method will be used, (2) a hydrograph of total flow and estimated base flow will bedisplayed on the screen for each year of data processed, and (3) an annual summary table willbe included in the print file if 3 or more years of data from the same station are processed.

HYSEP

Card Wdm Output Plots Method Execute

File Select

Open Close Summarize Add Drop List Clear Sort Browse Find Input Output

Query

Fixed LocalSliding

Figure 10. Hierarchy of menus in HYSEP.

(see figure 11)

19

Yes

No

Figure 11. Processing steps following selection of the Execute option.

Is drainagearea includedin data set?

Werefrequency

distribution, flowduration, or seasonal

distribution plotsrequested?

Has entireperiod of data

been processed?

Wasgraphical

hydrographrequested?

Execute Option

Specify base name foroutput files and period of

data to be processed.

One year’s worthof data processed.

Have all stationsbeen processed?

Specifydrainage area.

Graphicalhydrographgenerated.

Yes

Requestedplots

generated.

Yes

No

Yes

NoReturn toOpeningscreen.

No

No Yes

20

SPECIFYINGINPUT FILES

If input data are in a WATSTORE daily values format file,

Choose the Card option by typing “c”, or execute Accept (F2) while the Card option ishighlighted.

Type the name of the input data file on the file name screen [Card (C)] that appears.

Execute Accept (F2) to open and read the file.

If input data are stored in a WDM format file,

Choose the Wdm option.

Choose File from the Wdm (W) menu to specify the name of the WDM file. The File(WF) menu will appear containing operations that can be performed on a WDM file,including opening, closing, or summarizing the contents of the file. The Close option isused to close the current WDM file so that another file can be opened. The Summarizeoption displays general information on the WDM file.

Choose Open and type the name of the WDM file on the file name screen [Open (WFO)]that appears.

Execute Accept (F2) to open the file.

Choose Return to return to the Wdm (W) menu.

Choose Select to specify the stations—stored as numbered data sets in the WDM file—to be included as input to the HYSEP program.

SELECTING WDM FILE DATA SETS

The Select (WS) menu contains options for manipulating the data-set buffer. This buffer is anarray that contains the number of each data set selected for use in the hydrograph analysis. Uponfirst reaching this menu, the buffer will be empty. Data-set numbers can be added to the bufferby choosing the Add, Browse, or Find options.

Add

If the data-set numbers for the stations in the WDM file are known, the data-set numbers maybe added directly to the buffer by use of the Add option. To add data-set numbers directly to thebuffer,

Choose Add.

Type in the data-set numbers on the Add (WSA) screen, one per line.

Execute Accept (F2).

Up to 24 data-set numbers may be entered. Repeat the above steps to add more than 24 data-setnumbers to the buffer. Up to 300 data sets may be selected as input to the HYSEP program.

Browse

Choose the Browse option from the Select (WS) menu to scan through the WDM file to viewthe data sets currently stored. A screen containing two character input fields will appear(fig. 12). The source of data to be browsed is specified in the first input field. The entire WDM

1

2

3

1

2

3

4

5

6

1

21

3

21

file or just the currently selected data sets are browsed by specifying “WDM” or “BUFFER,”respectively. The contents of the second input field indicate what data-set information is to beincluded on the screen. The assistance window shown in figure 12 describes the types ofinformation that can be viewed; the Browse (WSB) screen after the Help (F1) command wasexecuted is shown in figure 12.

Upon Accepting the Browse (WSB) screen, one of the three screens shown in figure 13 willappear, depending on which type of data-set information was selected. Data-set number andtype and time-series type are displayed on all three screens. “TS”, representing “time series,”must be the data-set type of all WDM data sets used as input to the HYSEP program. The stringdisplayed under the time-series type column (“Tstype”) will generally be “FLOW,” “BFLO,”or “SRNF” indicating that the data set contains daily streamflow, estimated base-flow, orsurface-runoff values, respectively. If “na” appears in any column, that data-set information wasnot available.

Figure 12. Browse (WSB) data-set information selection screen.

22

Figure 13. Browse (WSB) data-set information screens.

23

Find

Choosing the Find option will display a menu of data-set characteristics [Find (WSF)] for whichvalues can be specified and used in searching the WDM file. To find data sets in the WDM fileon the basis of data-set characteristics,

Choose Find and, from the Find (WSF) menu, select one or more of the options shownin table 2.

After setting the search options, choose Execute to perform the search.

Once data sets have been selected by use of the Add, Browse, or Find options, several operationscan be performed on the data-set buffer by choosing other menu options:

List displays the contents of the buffer

Sort reorders the data-set numbers into ascending order

Drop eliminates a specific data-set number from the buffer

Clear removes all data-set numbers from the buffer

Output stores the data-set numbers in a file for later retrieval

Input retrieves data-set numbers from a file and places them in the buffer

To return to the Opening screen, choose Return from the Select (WS) menu and then chooseReturn from the Wdm (W) menu.

1

2

Table 2. WDM file data search options

searchoption usage

Type Specify the data-set type for the search. Although many WDM data-settypes are available, only time-series data sets can be used as input to theHYSEP program.

Number Specify a range of data-set numbers to search.

Attributes Enter values of data-set attributes for the search. Data-set attributes areancillary values and include station-identification number, latitude,longitude, drainage area, and basin slope, among many others. On-linehelp information on all WDM data-set attributes is available.

Subset Choose this option to perform the search operation only on those data setsalready in the buffer, thus selecting a subset of the currently selected datasets. Choosing Subset turns this option “on”; no screens are displayed bychoosing Subset. Once Subset is chosen, all searches performed willresult in a subset of the selected data sets. This option is turned “off” onlyby returning to the previous menu and choosing Find again.

24

SELECTING PROGRAM OUTPUT

Tables

Choosing the Output option from the Opening screen will display a form containing outputoptions (fig. 14). The five options on the upper left side of the screen refer to tables that can beincluded in the print file. In the default program setting, the print file will always contain anannual summary for the hydrograph separation if 3 or more years of data are processed. The firstmonth of the summary can be specified by typing in the abbreviation for the month. The Limits(F5) command will list the valid abbreviations for each month.

A monthly summary for the hydrograph separation and frequency, flow-duration, and seasonal-distribution tables can be included in the print file by typing “yes” or “y” in the correspondinginput fields. The frequency, flow-duration, and seasonal-distribution tables are produced onlyif 3 or more years of data are processed.

The two options on the lower left side of the Output (O) options screen (fig. 14) modify the unitsof values included in the print file tables. If “ENGLISH” units are chosen, the units listed on thenext line define the units used in a predefined column (shaded columns in Appendixes 1, 2, and3) in the monthly and annual summaries and in the frequency table. The English units that canbe chosen are included on the screen as option fields that are toggled on or off by pressing anykey. An “X” in the box to the left of one of the units indicates which units will be used. At leastone of the units must be specified to Accept (F2) this screen and continue.

All values in the print file can be converted to metric units by specifying “METRIC” in the“Units” input field. The metric units used in the predefined column (shaded columns inAppendixes 1, 2, and 3) are fixed regardless of the English unit chosen on the second line.

Figure 14. Output options screen.

25

Data Files

The options on the upper right side of the Output (O) options screen describe the forms ofcomputed output that can be produced. Daily values of estimated base flow and surface runoffcan be written to a file in the WATSTORE format or stored as data sets in the input WDM file.The data-set number assigned to each of these computed data sets will be the next free numberon the WDM file following the input data set from which it was computed. If you have notspecified a WDM file as the input data file, the WDM output options are not available and willnot appear on the screen. WDM output is saved only to the input WDM file.

Graphs

Selecting the Plots option on the opening screen brings up a form containing graphical outputoptions (fig. 15). Four plots can be produced:

1. a frequency-distribution plot of annual values,

2. a flow-duration plot of daily values,

3. a seasonal bar chart of mean monthly flows, and

4. an annual hydrograph of total flow and estimated base flow.

The annual hydrograph is produced for each year of data processed; the other three plots areproduced when 3 or more years of data from one station are processed. For each plot, two offour possible output devices may be chosen. These are specified under the “Device1” and“Device2” headings and include the monitor screen, a laser or dot matrix printer, a pen plotter,or a metafile.

Figure 15. Graphical output screen.

26

By default, total streamflow, estimated base flow, and estimated surface runoff will be includedin the frequency-distribution and flow-duration plots. Enter “no” or “n” for the input fieldscorresponding to these curves to eliminate them from the plots. Average monthly base flow andsurface runoff can be plotted in the seasonal bar chart or base flow and surface runoff as apercentage of the average monthly flow can be shown.

The query, “Do you want to modify the plots?” is included to streamline the process ofproducing graphical output. If the response is left as “NO,” the plots will be produced by use ofthe default plot parameters. If the response is changed to “YES,” plot parameters, such as axestypes, labels, minimum Y-axis value, maximum Y-axis value, plot size, title, and the color andline or symbol type for each curve, can be modified. Extra text can be added to each plot. Plotparameters need be specified only for the first time each plot is selected; all subsequent plotsproduced will include the modifications made to the first plot of that type.

The values for modified plot parameters generally are retained between each execution of thehydrograph separation. For example, if a set of stations is processed multiple times usingdifferent hydrograph-separation methods, a specific line type or color need be specified onlyonce for each type of plot selected during the first execution of the hydrograph separation.However, there are specific instances when the values for modified plot parameters are notretained. Whenever a new station is processed, the plot title will be reassigned using the stationname associated with the streamflow data. If the units specified under Output (O) are changedbetween executions of the hydrograph separation, y-axis labels that specify the units of the dataplotted also will be reassigned. For the frequency-distribution and flow-duration plots, curvespecifications such as line type or color and the curve labels used in the plot explanation will bereassigned default values when the curves to be plotted differ from those last plotted.

When the modification option is set to “YES,” the menu shown in figure 16 will be displayed.Regardless of the type of plot being produced, the menu displayed will be identical to the oneshown in figure 16; only the screen name will differ to reflect the plot type.

The Modify and Replot options can be chosen multiple times to change plot characteristics andre-create the plot. Once Done is chosen, the most recently modified plot parameters are used forall subsequent plots of that type.

Figure 16. Plot modification menu.

27

Modifying Plot Parameters

Choosing Modify from the menu shown in figure 16 will display the menu shown in figure 17.Each menu option allows modification of the following plot characteristics.

Device This option for choosing an alternate output device has been disabled withinthe HYSEP program because output devices are specified on the Plots (P)form.

Axes Axes types, such as arithmetic, logarithmic, or probability, can be specified.Additional axes, such as a right y-axis or an auxiliary axis, can be added oreliminated.

Titles The plot title and all axes labels can be modified.

Curves Curve characteristics, such as color, line type, or symbol used, can bechanged. The axis against which each curve is plotted also can be modified.The label for the explanation can be changed.

Min/Max The minimum and maximum value plotted on each axis can be modified. Ifthe minimum and maximum values are changed so that some points are nolonger plotted, several options are available to indicate where those pointswould have been plotted, or those points can be omitted entirely.

Extra Text may be added to the graph. The placement of that text, the number oflines of text, and the number of characters per line of text can be specified.The location of the explanation can be moved.

Size The plotting space dimensions, axes lengths, location of origin within theplotting space, and size of text lettering can be modified. If the HYSEPprogram is run on a computer using the X Window System, the position ofthe graphics window on the monitor can be modified.

Figure 17. Plot parameter modification menu.

28

SELECTION OF HYDROGRAPH-SEPARATION METHOD

By default, the fixed-interval hydrograph-separation method is used. To select anotherseparation method,

Choose Method.

Select a hydrograph-separation method from the menu options displayed.

EXECUTION OF THE BASE-FLOW SEPARATION

Before choosing Execute from the Opening screen menu, an input data file must be specified;and unless the default settings are being used, tabular and graphical output options and thehydrograph-separation method must be specified. After choosing Execute, the Execute (E)drainage area screen will appear only if the drainage area was not included in the input file.After entering the drainage area and pressing the Enter key, the screen in figure 18 will appearfor each station to be processed.

Specify a base name for output files. Appropriate suffixes will be added to distinguisheach type of file as shown in table 2.

Specify the dates of the data to be processed.

Execute Accept (F2).

Once Accept (F2) is executed on the base name and date specification screen, text screensdescribing the progress of the analysis will be displayed.

Each output file that is produced is assigned a name containing the base name specified on theExecute (E) station screen with a descriptive suffix appended. The base name can be modifiedeach time this screen appears so that the output files for each station can be distinguished fromone another. Alternatively, the same base name can be used for all stations processed during thesame execution of the hydrograph separation to distinguish different sets of stations processedtogether or to distinguish output produced when different hydrograph-separation methods oroutput options were chosen. If the same base name is used for all stations processed, one printfile will be produced that contains output for all of the stations. If a distinct base name is usedfor each station, separate print files will be produced.

When multiple output files of the same type are produced using the same base name, sequencenumbers are appended to the base name to distinguish the files from one another. For example,“.prt” is the file name suffix used to denote the print file; if the hydrograph separation isexecuted 10 times using the same base name, 10 print files will be produced having the names:basename.prt, basename2.prt, ... , basename10.prt. If frequency distribution plots are producedfor each hydrograph separation and the printer is chosen as the output device on a system wherePostScript graphical output is placed in a file, 10 files will be produced with the names:basenamefq.ps, basenamefq2.ps, ... , basenamefq10.ps.

The Intrpt (F6) command is available on the base name and date specification screen. Executingthe Intrpt (F6) command will return the program to the Opening screen, terminating executionof the hydrograph separation. This is helpful if you have selected multiple stations forprocessing and determine that you do not want to complete the hydrograph separation for all thestations.

1

2

1

2

3

29

Table 3. Output file name suffixes

tabular/computeddata output file suffix appended to base name

Print file .prt

Surface runoff, WATSTORE format .sro

Base flow, WATSTORE format .bsf

graphical output file1 suffix appended to base name

Printer2 Plotter3 Metafile4

Frequency distribution plot fq.ps fq.hpgl fq.cgm

Flow-duration plot fd.ps fd.hpgl fd.cgm

Seasonal bar chart sb.ps sb.hpgl sb.cgm

Hydrograph of base-flow separation hy.ps hy.hpgl hy.cgm1 Whether graphical output is placed in a file or sent directly to an output device is dependent on

the software library used to implement the Graphical Kernel System (GKS). Graphical output placed in afile will be appropriately formatted for the intended output device. The output file name will be composedof the user-specified base name and the suffix corresponding to the plot type and file format unless theoutput file name is fixed by the graphics software library. The README documentation that accompaniesthe program gives more information on system-dependent aspects of graphics generation.

2 Suffix .ps denotes a PostScript file.3 Suffix .hpgl denotes a Hewlett Packard Graphics Language file.4 Suffix .cgm denotes a Computer Graphics Metafile.

Figure 18. Base name and date specification screen.

30

SUMMARY

HYSEP is a computer program that can be used to separate a streamflow hydrograph into base-flow and surface-runoff components. Three methods of hydrograph separation are currentlyimplemented: fixed interval, sliding interval, and local minimum. These methods can bedescribed conceptually as three different algorithms to systematically draw connecting linesbetween the low points of the streamflow hydrograph. The sequence of these connecting linesdefines the base-flow hydrograph. The program also creates graphs showing the frequency andduration of measured streamflow and computed base flow and surface runoff.

The HYSEP program accepts daily mean stream discharge as input in either of two formats:(1) standard USGS WATSTORE daily values in an 80-character record ASCII format or(2) binary, direct access WDM System file format. Data for up to 300 stations in the WDMformat can be processed at one time. A minimum of 1 and a maximum of 100 years of data perstation in either format can be processed.

Program output options include tables, graphs, data files, and WDM data sets. All values in theprint files can be in English or metric units. Graphical output may be plotted on the computerscreen or output to a printer, plotter, or metafile. An annual hydrograph of total streamflow andestimated base flow can be plotted for each year of record processed. The year can begin withany day. Printed output for the hydrograph separation provides information on the quantity ofestimated base flow and surface runoff and on the percentage of streamflow as base flow andsurface runoff on an annual or monthly basis.

Frequency distributions of mean annual streamflow, estimated mean annual base flow, andestimated mean annual surface runoff for the period of record of a station can be plotted andprinted for any hydrograph-separation method. The program estimates a cumulative probabilitydistribution. Flow-duration curves can be plotted and a flow-duration table can be printed fortotal streamflow, estimated base flow, and estimated surface runoff. A bar graph can be plottedand a seasonal-distribution table can be printed for mean monthly estimated base flow andsurface runoff. Daily values of estimated base flow and surface runoff can be written to a file inthe WATSTORE format or stored as data sets in the input WDM file.

Program interaction takes place in a screen 80 characters wide by 24 characters high, which ismade up of three types of boxed-in areas referred to as panels. The data panel, displayed at thetop of the screen, contains menus, forms, tables, and text to permit user interaction with theprogram. The assistance panel, when present, is displayed below the data panel and containstext information, such as help messages, valid range of values, and details on program status.The instruction panel is displayed at the bottom of the screen and contains information on whatkeystrokes are required to interact with the program. Beneath the panels is a list of commandsfor obtaining additional information and moving between screens.

At a minimum, the input data file must be specified before executing the hydrograph separation.If no other program options are chosen, the hydrograph separation will be performed using thefollowing default settings: (1) the fixed-interval hydrograph-separation method will be used, (2)a hydrograph of total flow and estimated base flow will be displayed on the screen for each yearof data processed, and (3) an annual summary table will be included in the print file if 3 or moreyears of data are processed.

31

REFERENCES CITED

Flynn, K.M., Hummel, P.R., Lumb, A.M., and Kittle, J.L., Jr., 1995, User’s manual forANNIE, version 2, a computer program for interactive hydrologic datamanagement: U.S. Geological Survey Water-Resources Investigations Report95-4085, 211 p.

Linsley, R.K., Kohler, M.A., and Paulhus, J.L., 1982, Hydrology for engineers(3rd ed.): New York, McGraw-Hill, 508 p.

Lumb, A.M., Kittle, J.L., Jr., and Flynn, K.M., 1990, Users manual for ANNIE, acomputer program for interactive hydrologic analyses and datamanagement: U.S. Geological Survey Water-Resources Investigations Report89-4080, 236 p.

Olmsted, F.H., and Hely, A.G., 1962, Relation between ground water and surfacewater in Brandywine Creek Basin, Pennsylvania: U.S. Geological SurveyProfessional Paper 417-A, 21 p.

Pettyjohn, W.A., and Henning, Roger, 1979, Preliminary estimate of ground-waterrecharge rates, related streamflow and water quality in Ohio: Ohio StateUniversity Water Resources Center Project Completion Report Number 552, 323p.

Riggs, H.C., 1963, The base-flow recession curve as an indicator of groundwater: International Association of Scientific Hydrology Publication 63,p. 352-363.

———1968, Frequency curves: U.S. Geological Survey Techniques of Water-Resources Investigations, book 4, chap. A2, 15 p.

Rorabaugh, M.I., 1963, Estimating changes in bank storage and ground-watercontribution to streamflow: International Association of Scientific HydrologyPublication 63, p. 432-441.

Searcy, J.K., 1959, Flow-duration curves: U.S. Geological Survey Water-SupplyPaper 1542-A, 33 p.

Sloto, R.A., 1991, A computer method for estimating ground-water contribution tostreamflow using hydrograph-separation techniques: U.S. Geological SurveyWater-Resources Investigations Report 90-4162, p. 101-110.

Sloto, R.A., Cecil, L.D., and Senior, L.A., 1991, Hydrogeology and ground-waterflow in the carbonate rocks of the Little Lehigh Creek Basin, Lehigh County,Pennsylvania: U.S. Geological Survey Water-Resources Investigations Report90-4076, 83 p.

White, K.E., and Sloto, R.A., 1990, Base-flow-frequency characteristics of selectedPennsylvania streams: U.S. Geological Survey Water-Resources InvestigationsReport 90-4160, 67 p.

Williams, O.O., 1975, Daily values data entry and computation (program H475)—section Aof chapter IVof WATSTORE user’s guide: U.S. Geological SurveyOpen-File Report 75-426.

33

APPENDIXES

34

APPENDIX 1. ANNUAL BASE-FLOW SUMMARY

[Alternate English units can be used for the values in the shaded column. All values can be converted to equivalentmetric units. See the section “Selecting Program Output”; in, inches; ft3/s, cubic feet per second; Mgal/d/mi2, milliongallons per day per square mile; %, percent]

---------------------------------------------------------------

Annual base-flow summary

French Creek near Phoenixville, Pa.

Station ID = 1472157

Drainage area = 59.10 square miles

Local minimum method

---------------------------------------------------------------

Year starts in January

Year ends in December

---------------------------------------------------------------

Period ending in----------

ft3/s---------

Mgal/d/ mi2----------

% ofstream- flow----------

1969 6.201 27.00 0.295 64.751970 11.007 47.92 0.524 65.221971 13.665 59.49 0.651 54.911972 18.018 78.23 0.855 57.951973 16.380 71.31 0.780 61.171974 12.380 53.90 0.589 69.331975 16.123 70.20 0.768 61.881976 11.115 48.26 0.528 65.001977 10.803 47.03 0.514 56.591978 17.554 76.43 0.836 60.501979 17.561 76.46 0.836 55.701980 11.288 49.01 0.536 72.411981 5.517 24.02 0.263 63.371982 10.327 44.96 0.492 58.011983 15.474 67.37 0.737 57.421984 18.516 80.40 0.879 60.811985 8.375 36.46 0.399 61.211986 10.247 44.61 0.488 60.831987 10.354 45.08 0.493 61.441988 12.085 52.47 0.574 60.771989 15.437 67.21 0.735 65.611990 11.975 52.14 0.570 63.551991 10.751 46.81 0.512 72.081992 8.191

---------35.56--------

0.389---------

63.64--------

median 11.632 50.58 0.553 61.32

35

APPENDIX 2. MONTHLY SUMMARY

[Alternate English units can be used for the values in the shaded column. All values can be converted to equivalentmetric units. See the section “Selecting Program Output”; ft3/s, cubic feet per second; in, inches; BF, base flow; %,percent; Mgal/d/mi2, million gallons per day per square mile]

------------------------------------------------------------------------------

Hydrograph separation by the local minimum method




------------------------------------------------------------------------------

Period ending in 1969 interval = 5 days

------------------------------------------------------------------------------

Meanstream- flow(ft3/s)-------

Mean base flow(ft3/s)---------

Meansurfacerunoff(ft3/s)--------

Totalstream-flow (in)--------

Total base flow (in)---------

Totalsurfacerunoff (in)--------

BF/streamflow (%)---------

Base flow(Mgal/d/ mi2)---------

Jan. 42.87 31.56 11.32 0.836 0.616 0.221 73.60 0.345

Feb. 42.18 36.37 5.81 0.743 0.641 0.102 86.22 0.398

Mar. 57.45 41.56 15.89 1.121 0.811 0.310 72.34 0.454

Apr. 46.60 36.88 9.72 0.880 0.696 0.184 79.14 0.403

May 28.55 21.99 6.56 0.557 0.429 0.128 77.01 0.240

June 19.30 14.53 4.77 0.364 0.274 0.090 75.29 0.159

July 94.13 28.06 66.07 1.836 0.547 1.289 29.81 0.307

Aug. 30.39 24.18 6.20 0.593 0.472 0.121 79.58 0.264

Sept.

21.70 19.02 2.68 0.410 0.359 0.051 87.65 0.208

Oct. 22.48 19.96 2.53 0.439 0.389 0.049 88.76 0.218

Nov. 43.10 19.72 23.38 0.814 0.372 0.441 45.75 0.216

Dec. 50.48--------

30.48--------

20.01---------

0.985--------

0.595---------

0.390---------

60.37---------

0.333--------

41.70 27.00 14.70 9.577 6.201 3.376 64.75 0.295

36

APPENDIX 3. CUMULATIVE-DISTRIBUTION TABLE

[Alternate English units can be used for the values in the shaded column. All values can be converted to equivalentmetric units. See the section “Selecting Program Output”; cum dist, cumulative distribution; in, inches; Mgal/d/mi2,million gallons per day per square mile]

-----------------------------------------------

Annual base-flow summary ordered by frequency





-----------------------------------------------

Year starts in January

Year ends in December

---------------------------------------------

Cum dist-------

in-------

Mgal/d/ mi2-----------

year---------

4.0 5.517 0.263 1981

8.0 6.201 0.295 1969

12.0 8.191 0.389 1992

16.0 8.375 0.399 1985

20.0 10.247 0.488 1986

24.0 10.327 0.492 1982

28.0 10.354 0.493 1987

32.0 10.751 0.512 1991

36.0 10.803 0.514 1977

40.0 11.007 0.524 1970

44.0 11.115 0.528 1976

48.0 11.288 0.536 1980

52.0 11.975 0.570 1990

56.0 12.085 0.574 1988

60.0 12.380 0.589 1974

64.0 13.665 0.651 1971

68.0 15.437 0.735 1989

72.0 15.474 0.737 1983

76.0 16.123 0.768 1975

80.0 16.380 0.780 1973

84.0 17.554 0.836 1978

88.0 17.561 0.836 1979

92.0 18.018 0.855 1972

96.0 18.516 0.879 1984

37

APPENDIX 4. FLOW-DURATION TABLE

Flow duration table for total flow, local minimum method

at French Creek near Phoenixville, Pa. (1969-1992)

LowerClass

Cases equal orexceeding lowerlimit and less

than upper limit------------------------

Cases equal or exceeding lower

class limit------------------------

limit--------

Cases---------

Percent-----------

Cases-----------

Percent-------------

0.00 0 0.00 8766 100.006.90 0 0.00 8766 100.007.90 5 0.06 8766 100.009.10 6 0.07 8761 99.94

10.00 29 0.33 8755 99.8712.00 88 1.00 8726 99.5414.00 147 1.68 8638 98.5416.00 178 2.03 8491 96.8618.00 373 4.26 8313 94.8321.00 366 4.18 7940 90.5824.00 600 6.84 7574 86.4028.00 464 5.29 6974 79.5632.00 517 5.90 6510 74.2637.00 566 6.46 5993 68.3743.00 447 5.10 5427 61.9149.00 551 6.29 4980 56.8157.00 586 6.68 4429 50.5266.00 540 6.16 3843 43.8475.00 654 7.46 3303 37.6887.00 498 5.68 2649 30.22

100.00 568 6.48 2151 24.54120.00 195 2.22 1583 18.06130.00 303 3.46 1388 15.83150.00 308 3.51 1085 12.38180.00 152 1.73 777 8.86200.00 126 1.44 625 7.13230.00 129 1.47 499 5.69270.00 78 0.89 370 4.22310.00 64 0.73 292 3.33360.00 54 0.62 228 2.60410.00 42 0.48 174 1.98470.00 28 0.32 132 1.51540.00 25 0.29 104 1.19630.00 21 0.24 79 0.90720.00 14 0.16 58 0.66830.00 12 0.14 44 0.50950.00 6 0.07 32 0.37

1100.00 8 0.09 26 0.301300.00 4 0.05 18 0.211500.00 8 0.09 14 0.161700.00 1 0.01 6 0.071900.00 2 0.02 5 0.062200.00 2 0.02 3 0.032600.00 0 0.00 1 0.013900.00 0 0.00 1 0.015200.00 0 0.00 0 0.00

100000.00 0 0.00 0 0.00

38

Flow duration table for surface runoff, local minimum method


LowerClass


than upper limit------------------------


class limit------------------------

limit--------

Cases---------

Percent-----------

Cases-----------

Percent-------------

0.00 2130 24.30 8766 100.000.10 8 0.09 6636 75.700.12 1 0.01 6628 75.610.13 8 0.09 6627 75.600.15 7 0.08 6619 75.510.18 10 0.11 6612 75.430.20 16 0.18 6602 75.310.23 12 0.14 6586 75.130.27 13 0.15 6574 74.990.31 63 0.72 6561 74.850.36 22 0.25 6498 74.130.41 39 0.44 6476 73.880.47 56 0.64 6437 73.430.54 51 0.58 6381 72.790.63 113 1.29 6330 72.210.72 72 0.82 6217 70.920.83 79 0.90 6145 70.100.95 143 1.63 6066 69.201.10 129 1.47 5923 67.571.30 124 1.41 5794 66.101.50 144 1.64 5670 64.681.70 92 1.05 5526 63.041.90 159 1.81 5434 61.992.20 197 2.25 5275 60.182.60 139 1.59 5078 57.932.90 212 2.42 4939 56.343.40 165 1.88 4727 53.923.90 202 2.30 4562 52.044.50 202 2.30 4360 49.745.20 199 2.27 4158 47.436.00 213 2.43 3959 45.166.90 184 2.10 3746 42.737.90 222 2.53 3562 40.639.10 124 1.41 3340 38.10

10.00 239 2.73 3216 36.6912.00 201 2.29 2977 33.9614.00 204 2.33 2776 31.6716.00 166 1.89 2572 29.3418.00 200 2.28 2406 27.4521.00 167 1.91 2206 25.1724.00 189 2.16 2039 23.2628.00 169 1.93 1850 21.1032.00 168 1.92 1681 19.1837.00 150 1.71 1513 17.2643.00 125 1.43 1363 15.5549.00 152 1.73 1238 14.1257.00 133 1.52 1086 12.3966.00 96 1.10 953 10.8775.00 105 1.20 857 9.7887.00 76 0.87 752 8.58

100.00 121 1.38 676 7.71

39

120.00 36 0.41 555 6.33130.00 74 0.84 519 5.92150.00 79 0.90 445 5.08180.00 39 0.44 366 4.18200.00 60 0.68 327 3.73230.00 51 0.58 267 3.05270.00 33 0.38 216 2.46310.00 39 0.44 183 2.09360.00 24 0.27 144 1.64410.00 23 0.26 120 1.37470.00 20 0.23 97 1.11540.00 21 0.24 77 0.88630.00 12 0.14 56 0.64720.00 12 0.14 44 0.50830.00 5 0.06 32 0.37950.00 4 0.05 27 0.31

1100.00 8 0.09 23 0.261300.00 6 0.07 15 0.171500.00 3 0.03 9 0.101700.00 1 0.01 6 0.071900.00 4 0.05 5 0.062200.00 0 0.00 1 0.013400.00 0 0.00 1 0.014500.00 0 0.00 0 0.00

100000.00 0 0.00 0 0.00

40

Flow duration table for base flow, local minimum method


LowerClass


than upper limit-----------------------

-


class limit------------------------

limit--------

Cases---------

Percent-----------

Cases----------

-

Percent------------

-

0.00 0 0.00 8766 100.00

6.90 0 0.00 8766 100.007.90 7 0.08 8766 100.009.10 15 0.17 8759 99.92

10.00 64 0.73 8744 99.7512.00 176 2.01 8680 99.0214.00 303 3.46 8504 97.0116.00 259 2.95 8201 93.5518.00 410 4.68 7942 90.6021.00 501 5.72 7532 85.9224.00 813 9.27 7031 80.2128.00 531 6.06 6218 70.9332.00 596 6.80 5687 64.8837.00 672 7.67 5091 58.0843.00 478 5.45 4419 50.4149.00 567 6.47 3941 44.9657.00 673 7.68 3374 38.4966.00 623 7.11 2701 30.8175.00 606 6.91 2078 23.7187.00 538 6.14 1472 16.79

100.00 430 4.91 934 10.65120.00 123 1.40 504 5.75130.00 156 1.78 381 4.35150.00 156 1.78 225 2.57180.00 29 0.33 69 0.79200.00 22 0.25 40 0.46230.00 12 0.14 18 0.21270.00 5 0.06 6 0.07310.00 1 0.01 1 0.01360.00 0 0.00 0 0.00

100000.00 0 0.00 0 0.00

41

APPENDIX 5. SEASONAL-DISTRIBUTION TABLE

---------------------------------------------





---------------------------------------------

---------------------------------------------

Month---------

Base flow(inches)

-------------

Runoff(inches)------------

January 1.221 0.496

February 1.832 1.345

March 1.949 0.667

April 1.998 0.975

May 1.427 0.558

June 1.200 1.569

July 0.959 0.447

August 0.641 0.507

September 0.608 0.396

October 0.604 0.208

November 1.000 0.928

December 1.336 0.716

42

APPENDIX 6. SPECIAL FILES

Three files are associated with the interaction between the user and the program. The optionalTERM.DAT file is used to change some aspects of how the program operates. TheHYSEP.LOG file records keystrokes entered during a program session. Error and warningmessages are written to the ERROR.FIL file if problems arise during a program session. TheERROR.FIL file also can contain messages that document the processing sequence of theprogram.

A TERM.DAT file is used to override the default values of parameters that define theconfiguration of the computer system and the user’s preferences. The program looks for aTERM.DAT file in the current directory. The parameters include terminal type, the programresponse to the Enter key, and graphics options. Table 1 describes the TERM.DAT parametersshowing the default values as set for DOS-based computers, for DG/UX-based (DataGeneral/UNIX) computers, and for other UNIX-based computers. A parameter is overridden byspecifying its keyword and the new value in the TERM.DAT file. One record is used to defineeach parameter, with the keyword beginning in column 1 and the value beginning in column 8.

Many of the TERM.DAT parameters control graphical output, such as the specification of agraphics device, text font, symbol size, and background color. The values assigned to thegraphics parameters depend on the software library used to implement the Graphical KernelSystem (GKS). For information on overriding the graphics parameters on DOS-basedcomputers, see the README file distributed with the program. For other computer platforms,see the README documentation that accompanies the program and the GKS librarydocumentation for your system.

The value of the MENCRA parameter and the data panel type control how the programresponds when the Enter key is pressed. Table 2 describes the program response for the variouscombinations of MENCRA values and data panel type. The default value for the MENCRAparameter is "NEXT."

Table 3 shows an example TERM.DAT file that overrides the default BLACK backgroundcolor of the graphics display. The parameter BCOLOR is set to OTHER and the parametersBGRED and BGBLUE are set to 40 and 60, respectively. The resulting graphics screen displaybackground will be a shade of purple. In addition to the parameters described in table 1, thereare five parameters that can be used to set the foreground and background colors of parts of theprogram screen on DOS-based computers. These parameters are listed in table 4.

TERM.DAT

43

Table 1. TERM.DAT parameters

[GKS, Graphical Kernel System]

parameterkeyword

default valuesvalidvalues description

dos dg/ux otherunix

TRMTYP PC VT100 VT100 PCVT100OTHER

Terminal type.

MENCRA NEXT NEXT NEXT NONEDOWNNEXT

Program response to Enter key.

USRLEV 0 0 0 0 to 2 User experience level: 0=lots,1=some, 2=none.

GRAPHS YES YES YES NOYES

Is a software library for graphicsgeneration available?

GKSDIS 1 1100 4 0-99991 GKS code number for workstationtype for display terminal.

GKSPRT 2 102 4 0-99991 GKS code number for workstationtype for printer device.

GKSPLT 3 7475 4 0-99991 GKS code number for workstationtype for pen plotter.

GKSMET 4 24 4 0-99991 GKS code number for metafile.GKPREC CHAR STROKE CHAR STRING

CHARSTROKE

Text precision.

GKSCFT 1 1 1 -9999 to 99991 Text font for screen.GKPRFT 1 -2808 1 -9999 to 99991 Text font for printer.GKPLFT 1 1 1 -9999 to 99991 Text font for plotter.BCOLOR BLACK BLACK BLACK WHITE

BLACKOTHER

Background color of graphics screendisplay.

BGRED 0 0 0 0 to 100 Percent red for background ofgraphics screen display ifBCOLOR=OTHER.

BGREEN 0 0 0 0 to 100 Percent green for background ofgraphics screen display ifBCOLOR=OTHER.

BGBLUE 0 0 0 0 to 100 Percent blue for background ofgraphics screen display ifBCOLOR=OTHER.

PBCOLR WHITE WHITE WHITE WHITEBLACK

Foreground color of graphics screendisplay.

SYMSIZ 100 100 100 1 to 10000 Symbol size ratio in hundredths.TXTEXF 133 100 100 0 to 200 Text expansion factor in hundredths.TXTCHS 0 0 0 0 to 200 Text character spacing in hun-

dredths.1 Refer to GKS documentation and README file supplied with the program to determine valid

values for these parameters.

44

Table 2. MENCRA values and corresponding program response

mencradatapanel

contentsprogram response when enter is pressed

NEXT menu Same as if Accept (F2) were executed; the highlighted menu option is selectedand the program advances to the next screen.

form For all but the last field on the form, causes the cursor to advance to the nextfield. For the last field on the form, the response is the same as for Accept(F2)—the program advances to the next screen. (Note: usually the rightmost,lowest field is the "last" field in the form. Occasionally, however, it is not!)

table For each row, the cursor advances across the fields in the row. For all but thelast row, the cursor advances from the last field in the row to the first field ofthe next row. For the last row, the cursor advances to the beginning of the lastrow. (Use Accept (F2) to advance to the next page of the table.)

text Same as if Accept (F2) were executed—the program advances to the nextscreen.

NONE menu No effect—it is ignored.form Cursor is advanced to the next field. When the cursor is in the last field, the cur-

sor cycles back to the first field.table For each row, the cursor advances across the fields in the row. For all but the

last row, the cursor advances from the last field in the row to the first field ofthe next row. For the last row, the cursor advances to the beginning of the lastrow. (Use Accept (F2) to advance to the next page of the table.)

text No effect—it is ignored.DOWN menu Same as if the down arrow were pressed; the highlight bar moves to the next

menu option. When the highlight bar is on the last menu option, it returns tothe first menu option.

form Cursor is advanced to the next field. When the cursor is in the last field, the cur-sor cycles back to the first field.

table For each row, the cursor advances across the fields in the row. For all but thelast row, the cursor advances from the last field in the row to the first field ofthe next row. For the last row, the cursor advances to the beginning of the lastrow. (Use Accept (F2) to advance to the next page of the table.)

text No effect—it is ignored.

Table 3. Example TERM.DAT file

BCOLOR OTHERBGRED 40BGREEN 0BGBLUE 60

Table 4. TERM.DAT parameters for color display (DOS-based computers)

parameterkeyword

defaultvalue

allowablevalues1 description

CLRFRS 15 0 to 15 Standard foreground color.CLRBKS 1 0 to 15 Standard background color.CLRFRE 7 0 to 15 Foreground color for error messages in instruction panel.CLRBKE 4 0 to 15 Background color for error messages in instruction panel.CLRFRD 14 0 to 15 Color of first letter of commands in command mode.

1 0, black; 1, blue; 2, green; 3, cyan; 4, red; 5, magenta; 6, brown; 7, light gray; 8, dark gray; 9,bright blue; 10, bright green; 11, bright cyan; 12, bright red; 13, bright magenta; 14, yellow; 15, white

45

A file named HYSEP.LOG is created each time the program is run. This file contains thesequence of keystrokes entered during a program session. It may be used as an input to theprogram in a later session. To keep the sequence of keystrokes, you must rename the filebecause the program will overwrite any file named HYSEP.LOG. Keystrokes of nonprintingkeys, such as the backspace and function keys, are represented in the file by special codes. Table5 lists each code and its definition. Menu options are chosen in one of two ways—either pressthe first letter(s) of a menu option, or position the cursor with the arrow keys and then Accept(F2). Using the first method will make the log file easier to interpret and modify. Using the letter"x" for making option selections also will help. Table 6 contains an annotated example log filefor a program session that opens a WDM file and gets a summary of the contents of the file.

Log files can be used to easily repeat a task, or they can be modified to perform a similar task.A log file may contain all of the keystrokes required for a complete program session, or it maycontain the keystrokes for part of a program session. For example, all of the keystrokes neededto plot the results of a hydrograph separation can be saved and then reused for the nexthydrograph separation. A subset of a session might consist of the keystrokes required to selecta particular set of data sets; this log file would be used whenever that set of data was needed.

A log file may be entered at any point in the program by typing "@"; in the small panel thatappears, type the name of the log file. The program will run using the input from the file just asif it were being typed in. The program and the log file must be synchronized; if the keystrokesin the log file get out of sync with the program, the program response may produceunpredictable results. A common cause of synchronization problems involves output files. If anoutput file did not exist when the log file was generated and does exist when the log file is readby the program, the program may ask if it is OK to overwrite the existing file. Because thekeystrokes required to answer this question are not in the log file, the program will probably dosomething unexpected.

HYSEP.LOG

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Table 5. Codes used for nonprintingcharacters in a log file

code user’skeystroke

associatedcommand

#227 ; or Esc1

#208 Backspace#213 Return or Enter#301 ↑#302 ↓#303 →#304 ←#307 Page Up#308 Page Down#401 F1 Help#402 F2 Accept#403 F3#404 F4 Prev#405 F5 Limits#406 F6 Intrpt#407 F7 Status#408 F8 Quiet#409 F9 Xpad

1 The Escape key is only functional on DOS-basedcomputers.

Table 6. Description of example log file

line contents explanation

1 fotest.wdm TheFile option was selected from the Opening screen menu. TheOpen option was selected from the File (F) screen menu. The filenametest.wdm was entered in the Open (FO) screen.

2 #402 Accept, function keyF2, was executed, causing the test.wdm file tobe opened.

3 s TheSummarize option was selected from the File (F) screen menu.4 #402 After the summary of the contents of the test.wdm file had been

viewed, Accept, function keyF2, was executed.5 rr TheReturn option was selected from the File (F) screen menu. The

Return option was selected from the Opening screen menu.

hysep: a computer program for streamflow hydrograph separation and analysis · 2001-08-08 · hysep...

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